Hot-blast pyrometer



(No Model.)

B. BROWN.

HOT BLAST PYROMETER. Patented Sept. 20, 1881..

u. Pains, Phalo'lnhographnn Washmglon, a. c.

UNITED STATES PATENT OFFICE.

EDWARD BROWN, OF PHILADELPHIA, PENNSYLVANIA.

HOT-BLAST PYROM ETE R.

SPECIFICATION forming part of Letters Patent No. 247,157, datedSeptember 20, 1881.

Application filed March 19, 1881. (No model.)

To all whom it may concern:

Be it known that I, EDWARD BROWN, of 311 Walnut street, Philadelphia,Pennsylvania, have invented a new and useful Hot-Blast Pyrometer, ofwhich the following is a speeification.

Theobject of my invention is to indicate the temperature of thehot-blast used at iron smelting-furnaces, where a blast above red heatis produced by regenerative fire-brick stoves.

The invention is an improvement upon my patentofJune1,1869;auditconsists,briefly,in the combination of a pyrorueter-uozzle havinginlets for hot and cold air, with the metal expansionbar of thepyrometer inclosed in a conducting-tube, the expansion of the said barcommunicating its motion through a lever to the pointer of a dial whichis fixed upon a nonexpandingbar outside of the conducting-tube also, inthe construction of the nozzle of the pyrometer with a valve having astop or screw, whereby the relative proportions of hot and cold air maybe accurately adjusted and fixed at any desired proportion; also, in thecouvertible feature of the instrument, either to indicate the lowertemperature from iron stoves by the full heat upon the expansion-bar orthe red-hot blastfrom regenerativefire-brick stoves by a fixed relativeheat.

Figure 1 is an elevation of the pyrometer, partly in section. Fig. 2 isa front elevation, showing the double dial. Fig. 3 is an outside view ofthe cold-air inlet and valve.

A is a hollow tapering nozzle, of cast-iron, having a flange, a, and aguard of sheet-brass, 0. to deflect the blast away from the operatorshand. The nozzle A is screwed to or cast as a part of the hollow castingB. The casting B is bolted rigidly to the mahogany bar 0. Au iron pin,b, passes through this casting B, and also through the expansion-bar Dof the pyrometer and through the conductor 6. The conductor 6 is of thinsheet-iron, inclosed in a brass tube, 0 the latter being secured to thecasting B. This double conducting-tube e c slides in a ring, F, at theupper end. The ring F is fastened rigidly to the mahogany bar 0. Theupper end of the thin expansion-bar D is pivoted to the lever B, whichrocks upon the fulcrum h in the forkedjoint K. Thejoint K is securedrigidly to the mahogany bar 0.

At the opposite end of the lever there is an adjusting-screw, m,jointedat its lower end to the connecting-link n. This link, entering the gage,is connected with a lever which moves the toothed segment and pinion ofthe pointer L, common in steam-gages, and by this means the elongationof the bar D is communicated to the pointer L upon the dial. The dial isdouble, having one row offigures to 1,800 the other row to 1,200 or someother definite proportion of the larger number, as one-halt, onethird,three-quarters.

The casting B, with a conical nozzle, A, is hollow, and has drilledthrough it one or more cold-air inlets,W,which are covered by aspringring, S, which slides stifliy and can be moved on or off the holesW. A screw, S, passing through a slot, is used to secure the ring orvalve S in its place after being adjusted. The conducting-tube 6projects into the castiu g B beyond the end of the expansion-bar I), andterminates just above the air-inlets W. A tube, P, is screwed into theend of the nozzle A and projects in to the end of the conductor 0.

The instrument is operated and adjusted in this manner: First, cover theinlets W with the sliding valve S, remove the small interior pipe P, andthe instrument can be used to admit the full temperature of the blastupon the expansion-strip up to red heat about, 1,000 to 1,200 When the.same instrument is required to indicate the hot-blast from regenerativestoves where the temperature may be 1,800 the tube P is inserted and thevalve S brought to cover so much of the holes as may be requisite.Theinstrumentwithoutmyimprovement is tested at some temperature below1,200 We will assume it is lowered for the experiment to 900 of blast,as indicated by the outside dial; the tube P is then inserted and coldair admitted by the valve until the pointer shows 600, or two-thirds ofthe heat on the same outside dial. This in reality is 900 of blast, asshown by the inside dial, but only 600 upon the expansion-bar. Theinside dial may be omitted and the temperature calculated by addingfifty pereen t. Thus 800 plus 400 equals 1,200 of blast. The pointerhaving started at 0 Fahrenheit, the temperature of the atmosphere mustbe added to 1,200 for perfect accuracy. This interchangeableconstruction gives every furnace-tender the means of testing andadjusting his own instrument according as the pressure of blast or thetemperature of the cold air may vary from one season of the year toanother. The expansiontube of the ordinary Gauntlett pyrometer may beinserted within the conductor 6; but the combination is inferior to theone shown, 0wing to the longer time required to take an indieation.

By this construction I obtain an instrument accurate and durable, easilytested and adjusted to a high or low pressure of blast, and convertiblefrom a low-temperature instrument to one indicating the highestpractical temperature of blast attainable at present.

I do not broadly claim the mixing of cold air with the hot-blast andindicating the same, but theparticular combination of devices whichaccomplish that end.

1. Ina hot-blast pyrometer, the combination of a nozzle having aninlet-pipe for hot air and a cold-air inlet capable of being closed oradjusted to different areas, a metal expansionbar, a conducting-tubeinclosing sald bar and surrounding the upper end of the hot-air inlet,and alever connecting with the expansion-bar and with the pointer of thedial, substantially as and for the purposes set forth.

2. In a hot-blast pyrometer, a device adapting the instrument for lowand high temperatures, consisting of the nozzle A, a cold-air inlet, andmeans for closing it or decreasing its area, combined with the hot-airinlet P, substantially as set forth.

3. The nozzle A, having cold-air openings and means for closing them ordecreasing their area, the conducting-tube e, and the hot-air inlet I,the upper end of which extends with,- in the conducting-tube, combinedwith the expansion-bar l), substantially as and for the purposes setforth.

4. In a hot-blast pyrometer, the combination of a hot-blastinlet, P, acoldair inlet controlled by a valve, an expansion-bar within theconductor e, which operates apointer, and adouble dial having the spacesof one of them in a fixed proportion to the spaces of the other, so thatthe same instrument is interchangeable either for use with the fulltemperature or with mixed hot and cold air.

EDWVARD BROWN.

I Vi tnesses:

PARK MFARLAND, J r., JOHN F. GRANT.

